It is known that, in order to effect this detection, receptacles are used containing a layer of growth media such as agar for receiving microorganisms coming from the environment which it is wished to monitor, the receptacle next being put to incubate at the required temperature and for the required time to enable the microorganisms received to develop in the form of colonies visible to the naked eye, so that they can be counted and identified.
The microorganisms are collected, according to the degree of accuracy sought, passively, for example with a petri dish that is left open for a few hours with the layer of growth media exposed to air in order to collect microorganisms by sedimentation, or actively, that is to say by depositing, under known conditions, microorganisms coming from a sample of predetermined volume of the medium which one wishes to monitor.
The invention aims to increase the accuracy of detection, in particular in the case of an active collection of microorganisms.